Hello all,

I have a 1968 Camaro RS with a 350 .060 over, alum heads, 9.5:1 compression, 670 cfm holley carb, alum intake, etc. The other day I was going down an off-ramp from the interstate no the HOT ROD POWER TOUR, pushed in the clutch, and the engine died. I thought this was odd. Started it, and heard a valve tick/rocker noise I hadn't heard before. I then drove to the nearest gas station to investigate. First I checked the oil. It was somewhat low, so I filled it up. Started the car and still heard the noise coming from the passenger side. then I took off the valve cover and watched the rockers. they all looked the same but I heard the sound coming from the No. 2 cylinder intake rocker. I loosened the lock allen head bolt and then started the motor. I tightened the rocker some and the sound went away at idle, but as soon as I revved the motor, the sound came back and went away as the rpm went back to idle. The motor didn't miss. I tightened it more, and each time I did, the sound came back, but at a higher rpm each time. After three tightenings and oil all over the headers, I tightened the lock nut, put the valve cover back on, and drove home. The entire way, I drove easy (under 3000 rpm) but I could hear the tick distinctly. When I got home, I could hear the tick at idle, but only barely. I am very concerned. I have talked to alot of people, including Lunati, who manufactured my cam. It is a hydraulic flat tappet cam 225/235 @ .050" duration, .477/.488 lift, and 112 deg centerline on a 4 deg advance from the crank cog. The motor has about 2500-3000 miles on it and was broken in properly. I haven't had any problems out of it whatsoever as far as valvetrain goes. The oil I use is SAE 5W30 Valvoline Conventional.

Stuck lifter? How long a drive did you take after you heard the noise? It should have unstuck itself if it was going to. Ironic that the noise started after you restarted your engine. Are you 100% positive it is internal noise? Does the noise accelerate with the engine? Can you watch the rocker and match the noise to that particular lifter/valve/rocker? Hope you figure it out, sounds like a lifter noise to me, hoping its not a bearing.

Take the filter off and cut it open to look for metal. Cam trouble?

If the rocker arms are fully moving up and down then the cam is ok. I would set that lifter 3/4 down from 0 lash and even add a bottle of GM EOS to see if it frees up the lifter.

I drove it about 20 mins, and 15 miles. The sound seems to cone from the rocker clattering. It could very well be the lifter, having trash in it. The reason I'm concerned is that when I called Lunati tech yesterday, the guy said that the cam lobe could very well go down as a result of not using a zinc additive. He suggested to first check the lift of the problem intake valve against other intake valves by measuring the lift of the pushrod and lifter by using a dial indicator. Some other friends of mine suggested changing the oil to 20w50 or 40 weight racing oil that has the zinc additive in it and run it some to allow the lifters to pump up . I'm just not sure what to do, don't want to hurt the motor any more that it nay already be hurt.

Two questions; did you use the correct break in oil that contained the high levels of zinc recommended for flat tappet camshafts?

Was the oil you ran after break in formulated with the minimum recommended about of zinc for a flat tappet camshaft?

Using a dial indicator to compare will show you for sure if you have a camshaft/lifter failure taking place.

You should do the check of the mechanical lift, as recommended by the cam supplier
If it's not within the manufacture's tolerance of the advertised lift then you should pull the filter, cut open at the seam and check for metal debris. Any indication of odd metal debris should be taken as a confirmed indication of an issue within and further tear down and inspection should commence to find the source.

You should not change oil type or introduce 'snake oils*' into the sump in hopes of finding if you can "un-stick" something - not on a performance oriented engine build anyway (hoping not to offend any used car salesmen here ...).
(* - although EOS is still one of the superior snake oil products [and I use it for break-in and continued additive support] - it can't fix an already hurt engine ...)

As always JMHO's

1st question: Yes, I used COMP Pro Can Lube for 20 min at 2000 rpm to get the lifters spinning.

2nd question: I don't know. From what I've Ben told by the older guys, no. I've been using Valvoline 5w30 conventional. Everyone has been saying that regular oil now does not have as much zinc in it as it should. So the answer to this is up in the air I suppose.

I learned the hard way on my engine. I ruined 2 cams before I found out what it was. Now I add ZDDP and have had no trouble.

-Chuck

Time and time again it is said do NOT add ZDDP additives to an existing oil! It messes up the additive package that the oil company has designed and put into their oil. If you need ZDDP, buy an oil that was made with elevated ZDDP levels at the refinery or packaging plant.

OP, all good ideas to check the lift. However, check your header bolts to make sure they are not loose. Sounds just like a ticking lifter.

A mechanics stethoscope reveals so much..
And a long screw driver held hard to the ear like a stethoscope reveal almost as much..
Either will local if lifter or tappets and which ones...

Also do it with tappet covers on....it is not unheard of to panic without counting to10 very slowly 1st , only to find a tappet gasket has shrunk slightly and a tappet is just touching it.. and it may not even leave a mark.. or touch at idle.

Yep measure the height lift as mentioned above...both at the lifter/ push rod and the tappet and compare to others and the cam spec.

Cams bearing etc MUST be run in on the manufactures install instructions which include the lubes...
I run a oil change after about 50/100 miles and never have used aftermarket oil additives...ESPEC on a new engine.... the oil companies spend millions on research, avoiding big court cases ... and we think we know different... or simply once again sucked into the Goebbels marketing propaganda BS....

These 2 snippets of info are interesting thu... I assume the engine was oprginally fired up run in... then oil levels checked and topped up if needed , or changed, and refilled to correct levels ???? For the level to drop that far in that many miles I wounder if the rings have bedded in , or maybe a collapsed and/or cracked piston skirt?

If what sounds like a lifter/ tappet but have difficulty locating the sound source with a stethoscope.... including from under the car on a hoist....
you have a big carb, most properly not ball park dialed in, when firing up someone most properly swinging on the dizzy to get it to fire, fires , they leave it there rather than retard a bit... take the rpms up to bed rings cam etc, over advanced , and rich... big heat in pistons and one grabs a wall....Often the tap is not heard for some time/ miles later.
Hopefully not check out the other stuff 1st.

But that low oil is a worry.

The oil level was only slightly low as in maybe a quarter of a quart. I'm fairly certain that this is a lifter problem. Either there is trash in lifter, the bleed down isn't right because the oil is incorrect(lifter not pumped up), or the cam lobe is trying to round out l. I know it is a little problem because I tightened the lifter nut and the ticking went away. Each time I tightened the nut, the ticking came in at a higher rpm.

Ryan, I hate to bother you right now because you no doubt have your hands full removing the intake and pulling that lifter,,,,, but please give us a shout ASAP. This is maddening.

Prepare yourself for bad news.

If you did not use the proper break in oil you probably have a lobe going down.

If you did not do the proper break in procedure you probably have a lobe going down.

From Comp Cams

Proper Camshaft Break-In

Proper flat tappet camshaft set-up and break-in, as any engine builder knows, are keys to how
long a camshaft will last, both short and long term. The correct procedure allows the lifters to
establish rotation and develop a good wear pattern.


Break-In Preparation
Always remove the inner spring during break-in when using dual or high pressure valve springs.
An alternative solution that addresses this same concern is using a set of low-ratio break-in
rocker arms. Both of these solutions provide your best chance of proper camshaft break-in and
long term durability. While these tips may be a slight inconvenience, a little time and effort on
the front-end is much better than destroying your new engine.


Proper Procedure
As soon as the engine fires, bring the rpm up to 2000 to 2500 during the first 30 minutes of
operation. Slower engine speeds will not supply the camshaft with an adequate amount of oil for
the break-in period. The engine rpm may be varied periodically from 2000 to 2500 to direct oil
splash to different areas of the camshaft. After the 30 minute break-in period, change the oil and
filter again to be sure all contaminants and break-in lube are removed from the engine. The inner
valve springs should now be replaced and the correct rocker arms installed.

Unfortunately I haven't had time to check into anything. I probably won't have time until the weekend do so. like I said before, I broke the cam in properly(used Comp Cams Pro Cam Lube at 2000-2500 rpm for 20-25 min), I don't have high spring rate valve springs nor do I have high ratio rockers(1.5). The engine was run at 2000-2500 rpm for approx 20 min per the Lunati instructions. I'm no expert, but it stands to reason that if the break-in went well, which it did, it shouldn't be an issue now. I feel that the fact that the oil I've been using is zinc-starved has a lot to do with this. Either it is because the cam lobes did not have adequate oil on the lobe itself causing a "scuff" (an effect of low zinc levels) or the less viscous oil (5w30 20-25 psi at idle, 50-55 psi while moving/driving) has caused the lifters to become unhappy. I am young, thus I've never encountered things like this as of yet. I do know that this lifter/rocker noise is odd and loud, and it is scaring me. I'll try to check things out this weekend. I have a feeling this will prove to be an involved process. It is unfortunate that this has occurred smack-dab in the middle of show season....
Two bits of potentially useful info: 1. I don't run this motor hard. I've only had the engine speed over 5500 rpm once or twice when tuning the carb jets/ centrifugal advance.
2. I drive this car quite a bit, usually every weekend. It doesn't sit for extended periods of time like some other cars may. Even over winter I start it every two weeks or so.
Hope this helps some until I can dig into it this weekend. Thanks again everyone !